The invention relates to an arrangement for remotely controlling a mobile radio telephone in a motor vehicle, where the radio telephone is connected to a standard hands-free device which is installed as a stand-alone appliance in the vehicle and which contains a microphone and a loudspeaker. The invention also relates to an interface module for setting up a communication link between a radio telephone and an input unit and an output unit which are suitable for remotely controlling the radio telephone.
In line with legislation, mobile radio telephones in motor vehicles must be operated using hands-free devices for safety reasons. In this context, the standard design of a hands-free device essentially comprises a microphone and a loudspeaker and also an interface to the radio telephone. Optionally, a telephone receptacle may be provided into which the radio telephone is plugged during the journey. Standard hands-free devices are installed as stand-alone appliances in the vehicle. In the meantime, integrated systems are also being offered on the vehicle market which have the hands-free function implemented by means of an audio system which is already installed in the vehicle. To this end, the radio telephone is connected to the audio system either by means of a cable or by means of a short-haul radio link. Such an integrated system using a short-haul radio link is known from DE 19921533 C1, for example. Besides the provision of the hands-free function, the audio system described therein can simultaneously be used for operating the mobile telephone.
The approach to remotely controlling the radio telephone using control and/or display elements on a navigation, multimedia or audio appliance is also pursued in other systems available on the vehicle market, with either the radio telephone or a hands-free device developed specifically for the appliance in question being connected to these appliances. The control elements used are keys, rotary knobs or screens with a touch function, for example, while any kind of display may be used for the display.
All of these integrated systems, regardless of whether they are designed exclusively for hands-free talking or else for remote control, represent special solutions in each case which force the user to use exclusively appliance combinations which are matched to one another. The associated costs and the restriction to just a few types of radio telephones which are to be used mean that many car drivers prefer standard hands-free devices, which are much less expensive and can easily be adapted or even maintained when the radio telephone is changed.
Although standard hands-free devices have the hands-free function guaranteed, the car driver is reliant, for the purpose of operation, on the keypad and on the display of the radio telephone, which are not always easy to access or to identify during the journey. Some standard hands-free devices therefore have provision for voice operation or are equipped with an additional remote control and display. Drivers use voice operation only reluctantly, however. There is generally a natural threshold of inhibition for speaking to technical appliances, and this threshold of inhibition is increased further when there are other people present in the vehicle.
US-2002/0032042-A1 discloses a mobile telephone holder for a motor vehicle with an integrated voice control function for the mobile telephone. The telephone holder can have an external appliance connected to it which can then likewise be operated by voice input.
U.S. Pat. No. 629,183 describes an interface device for transmitting information between input/output means and application appliances. The application appliances, such as radio, CD player, mobile telephone, navigation system or onboard computer, are connected via the interface device directly to input means, such as a keypad, rotary/push control, microphone or video camera, and also to output means, such as a screen or loudspeaker.
On the Internet, an article has been published with the title “Universeller Bluetooth-Adapter für Auto-Freisprechanlage” [Universal Bluetooth adapter for car hands-free installation] on 2002 Nov. 6 at the address www.heise.de/newsticker/meldung/32125. The Bluetooth adapter is connected to arbitrary hands-free devices by means of a cable. A mobile telephone equipped with a Bluetooth interface can then be connected to the hands-free device by means of Bluetooth. The adapter has special keys which can be used to control a few functions, such as accepting or ending a telephone call or setting the volume.